Incandescent lamp stem



Feb. 5, 1935.

J. A. DONOHOE 1,989,791

INCANDESCENT LAMP STEM Original Filed May 18, 1929 INVENTOR I Q.flO/VQf/OE Patented Feb. 5, 1935 INCANDESCENT LAMP STEM James A.Donohoe, Bloomfield, N. J., asaignor to Westinghouse Lamp Company, acorporation of Pennsylvania Original application May 18, 1929, SerialNo. 364,116. Divided and this application June 22, 1932, Serial No.618,709

3 Claims. (Cl. 176-36) This invention relates to the manufacture of willbe drawn out of the arbor as well as the bulb. stems for incandescentelectric lamps or similar It has been found that lamp stems made inacdevlces and is a division of application Serial cordance with theabove practice present certain Number 364,116 filed May 18, 1929 forIncandesdisadvantages. Difilculty has been experienced in 5 cent lampstems Patent No. 1,908,736. providing the aperture in the button sincein 5 The manufacture of incandescent electric lamps forming thisaperture it is necessary to employ a includes an envelope or bulb intowhich is sealed pointed tool which has a tendency to adhere to what istermed a lamp mount. The mount usualthe glass throwing the button out ofproper posily consists of a flare tube, an exhaust tube, an tion withrespect to the arbor and since any defarbor, as well as a pair ofleading-in conductors ormation with repect to the position of the but-10 all of which are consolidated in what is termed ton results indifllculties in connection with the a press to constitute a unitarystructure. This insertion of the support wires, stems made in thestructure is termed a stem and is ready to have above manner presenteddisadvantages from a support wires inserted into the arbor and afllamanufacturing standpoint.

ment mounted on the support wires. After the The support wire insertingmechanism operates 15 support wires and the filament are in place and toinsert the support wires by movement through the filament is connectedwith the leading-in definite paths and when the button is notpropconductors the structure is termed a mount. erly positioned the pporwires will be inserted The present invention is concerned with the aninsuiiicient depth or not inser ed a wi h manufacture of stems to becompleted as mounts the result that the automatic mechanism which 20 asconstitute the internal structure of electrical must operate atrelatively high speed is attenddevices, such as incandescent electriclamps. ed by an appreciable amount of loss through de- It has beenproposed to construct a lamp stem fective stems. by supporting a lengthof glass tubing disposed It is an object of the present invention toproin axial alignment with the longitudinal axis d a p S in a l w a borand.v a 25 of a glass flare tube. A pair or leading-in wires uniformlyformed and accurately positioned butare also positioned within the flaretube and heat ton nis applied adjacent to the unflared end of the n th ro ject of the invention is o Provide a flare tube at which time the saidend is comlamp tem h v n a nifo y p i n d button pressed, forming whatis termed a press so as to and n ap r r for ha n the ar r. 3o fuse andconsolidate the flare tube and the in- Another object of the inventionis to provide a temally supported tube together, as well as to method ofproducing a lamp em having 8 h lseal-in the leading-in wires at thepress portion. low ar r n a button f r ivin upport wires Means areprovided for directing a jet of air and for closing an end of saidarbor.

under pressure into one end of the centrally sup- Other objects andadvantages of the invention 35 ported tube, while the portion termed thepress i will be more fully understood with reference to still plastic sothat the wall of the flare tube is the following descript together withthe acpunctured and an aperture is provided for como mp y n drawing. inwhich munication between the internally supported tube Fi 1 ShOWS a pStem a g a ho low arand the interior of a lamp bulb for exhaust purborready to b P d h an perture. 40 poses after the stem has been sealed tothe bulb. 2 is a Side View 01 the Stem Shown in Fig.

When constructing a lamp stem as above de- 1 with a flame in positionfor heating a portion scribed the portion of the central tubular memofthe wall oi. the arbor. ber extending from within the flare tube is uti-3 is a vi w of a stem shown n i 2 with lized as the exhaust bulb and theend of the tubuan arbor having a hole therein and with a nozzle 45 larmember projecting outwardly from the press in posi n r directing under Psure into is utilized as an arbor to receive support wires. the a bo Forthe purpose or obtaining material to receive Fi 4 is a View Similar to 2h win n the ends or support wires, which carry the fllaanne ng fir r d uan aperture in the ment, an end of the arbor is rendered plastic andarbor. 50 compressed into what is termed a button at which Fig. 5 is aview of a stem with means for formtime means are provided for leavingthe top of ing a button at the end of an arbor, and the button open soas to afiord communication Fig. 6shows an arbor constructedin accordanceto the interior of the hollow arbor. This is necwith the presentinvention and complete to supessary so that when the bulb is exhaustedall gases port a lamp filament.

In practicing the present invention stems may be provided comprising anexhaust tube a flare tube 11 and an arbor 12. The arbor and flare tubewhich are initially of a continuous tubular member are united to theflare tube at 13 in what is termed a press which results from pressurebeing applied to heated portions of the positioned glass parts. Leadwires or conductors 14 and 15 extend through the press and are sealedtherein.

A stem constructed as above described may then 10 be supported and heatprovided by a flame 16 which may be directed against a wall 1'? of thearbor 12. When the wall is heated to the proper plasticity a nozzle 18directed air under pressure into the arbor so as to puncture the wallthereof at the plastic portion, and an aperture 19 is provided. Theperimeter of the aperture 19 may then be annealed by directing a flame20' thereagainst.

.The stem may then be properiy supported and the exposed end 21 of thearbor may be heated by a flame 22 until plastic, at which time apressure member 23 may be moved to engage the plastic end and form abutton 24, at the same time closing the end of the arbor and producing asolid symmetrically positioned mass for the insertion of support wires25 which may be applied by mechanism 26, comprising the usual insertingram of a support wire inserting machine. After the support wires areinserted they may be bent upwardly as shown in Fig. 6 and a filament 2'7may be mounted therein and the ends of the filament suitably secured tothe lead wires 14 and 15.

A lamp stem constructed in accordance with the present method isprovided with a hollow arbor having an end closure in the form of abutton which is so positioned as to lie in a plane transverse to thelongitudinal axis of the arbor. It is therefore possible to provide aglass mass into which the support wires may be securely and deeplyembedded, and furthermore by reason of the provision of an aperture inthe side wall of the arbor a larger opening is possible than hasheretofore been obtainable and a more complete exhaustion of theinterior of the arbor is attained.

It wili be understood that in the manufacture of an articie such asanincandenscent electric lamp it is extremely important that the variouslamp parts be made with the proper degree of uniformity so as to meetthe requirements of subsequent operations on other machines, and where alamp part is made of such character that its physical accuracy cannot bedepended upon, considerable loss is incurred causing shrinkage andobviously increasing the cost of production.

By reason of the present invention a lamp stem is" produced by a simpleand convenient method and at the same time the required uniformity tomeet practical manufacturing demands is attained.

Although a preferred embodiment of the invention is shown and describedherein it is to be understood that modifications may be made thereinwithout departing from the spirit and scope of the inventiori as setforth in the appended claims.

What is claimed is:

1. A glass lamp stem having a hollow arbor closed at one end by acompressed glass mass an enlarged glass mass closing the other end ofsaid arbor, said arbor having an aperture in the cylindrical wallthereof intermediate its ends.

2. A lamp stem having a hollow arbor closed at one end by a press; abutton formed from the material of said arbor closing the other endthereof, said arbor having an aperture in the o3 lindrieal wall thereofadjacent to said last mentioned' end.

3. A lamp stem comprising a flare tube, a hollow arbor, a press forconsolidating said flare tube and closing one end of said arbor, anexhaust tube extending from said press, an aperture in said presscommunicating with said exhaust tube, the free end of said arbor beingclosed by an enlarged mass, said arbor having an aperture in thecylindricai wall thereof.

JAMES A. DONOHOE.

